I have seen people use those flashingh LED light that cyclists use. Maybe on the top of a hat? On the back of a PFD and then a head lamp would be good too. Don't want to wreck your night vision.
Now, what to do during the day. "That guy sees me...he must...YIKES! That was close! Did you see the expression on his face? Phew!". Sailing yatchs are especially dangerouse. They already ply the waters assuming that they ALWAYS have right of way. Try not to be possitioned down wind of them. It's hard to see behind the sail.